1. Field of the Invention
The present invention relates to a control panel assembly mounted to an electric home appliance such as a drum washing machine, and more particularly, to a button assembly of such a control panel assembly, which has a structure capable of guiding, to a desired position, water penetrating the interior of an electric home appliance when a button included in the button assembly is pressed.
2. Discussion of the Related Art
Generally, a control panel assembly, which includes buttons to enable diverse functions, is mounted to an electric home appliance such as a washing machine, a drum washing machine, or a drying machine. Although such a control panel assembly is applicable to various electric home appliances, the following description will be given only in conjunction with a control panel assembly applied to a drum washing machine.
FIG. 1 is a perspective view schematically illustrating the outer appearance of a conventional drum washing machine. As shown in FIG. 1, the conventional drum washing machine includes a cabinet 10 which defines the outer appearance of the drum washing machine, and a door 50 mounted to an opened front wall of the cabinet 10 to allow clothing to be put into the interior of the drum washing machine through the front wall of the cabinet 10. The drum washing machine also includes a tub (not shown) disposed in the cabinet 10 to contain washing water, and a drum (not shown) rotatably disposed in the tub (not shown) to carry out a washing function.
Meanwhile, a control panel assembly is mounted to an upper portion of the front wall of the cabinet 10, in order to control the drum washing machine to perform a selected operation. The control panel assembly includes a plurality of buttons for enabling diverse control operations for the drum washing machine, respectively.
FIG. 2 is an exploded perspective view illustrating the control panel assembly included in the above-mentioned conventional drum washing machine. As shown in FIG. 2, the control panel assembly includes a printed circuit board (PCB) 40 provided with a certain circuit, a control panel 20 which covers the PCB 40, and is provided with a plurality of button holes 21, and a button assembly 30 attached to an rear surface of the control panel 20, and includes a plurality of buttons 31 protruded through the button holes 21, respectively.
In addition to the buttons 31, the button assembly 30 includes a vertical rib 32 attached to the rear surface of the control panel 20, and a plurality of vertically-arranged horizontal ribs 33 each having one end connected to the vertical rib 32. Each of the buttons 31, which is protruded through an associated one of the button holes 21, is connected to the other end of an associated one of the horizontal rib 33. A fastening hole 30a is provided at the vertical rib 32. A screw is fastened to the rear surface of the control panel 20 through the fastening hole 30a, so as to attach the button assembly 30 to the rear surface of the control panel 20.
Referring to FIG. 3, which is a sectional view illustrating the attached state of the control panel 20, each button 31 has a convex structure such that the button 31 has a portion forwardly protruded through the associated button hole 21. Each button 31 also has a protrusion extending from a rear surface of the button 31 to a predetermined length.
The PCB 40 includes a plurality of key pads 41 arranged on the PCB 40 at positions respectively corresponding to the protrusions 34 of the buttons 31. Each key pad 41 is connected to a microcomputer (not shown) to send to the microcomputer a key input for execution of a predetermined operation of the drum washing machine when the key pad 41 is pressed. Accordingly, when a selected one of the buttons 31 is pressed, the corresponding key pad 41 is pressed, thereby enabling the microcomputer (not shown) to control the drum washing machine to perform an operation associated with the pressed button 31.
However, the above-mentioned conventional control panel assembly has a drawback. That is, if the user presses a selected one of the buttons 31 using his finger under the condition in which the finger is wet, water on the finger may penetrate the interior of the control panel 20 via the button hole 21 corresponding to the pressed button 31. In this case, the water, having penetrated along the button hole 21, may flow to the immediately lower button 31 or to the inner bottom surface of the control panel 20, so that the water may splash. In severe cases, the splashed water may splash up to the PCB 40.
For example, water penetrating the button hole 21 corresponding to the button 31 arranged at an uppermost position a may be quickly dropped without any resistance to the button 31 arranged at a position b, c, or d downwardly spaced apart from the uppermost position a by a distance causing the dropped water to splash, as shown in FIG. 2. Also, the water may be directly dropped to the inner bottom surface of the control panel 20. In either case, the dropped water splashes naturally. In this case, the splashed water may come into contact with the PCB 40. When such a phenomenon occurs during operation of the drum washing machine, the circuit of the PCB 40 may be short-circuited or opened, thereby causing the drum washing machine to malfunction or fail completely.